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Help w/ pusher fan---not cooling fast enough at idle


BDB

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hi gents,

you'd figure after reading about a dozen electric fan install threads, i'd get it right the first time but my electric fan is just not pushing down the temps at idle.

Ok, here goes:

- new water pump

- recored (2 only) radiator OEM

- new coolant (50/50 mix)

- new 71C thermostat

- installed hayden 10" (might be 11", but lets say 10" for now) fan bought from a member on the forum.

- installed hayden thermo relay + thermostat probe style kit. was easy to install just time consuming doing it.

What I've done and what is happening:

- bled cooling system by running heater on full blast and ran for nearly 20 minutes

- wired fan to be a pusher. set fan at middle setting. while engine was warming up, the fan wouldn't kick in. so i turned the dial about a 1/4" way from the bottom. fan kicked in as the temp needle was just hitting/reading mid point (stock temp gauge)

so to be extra safe, i drove it around the block (cap on of course) a few times until the temp needle got a hair above the 1/4 point. so here's what i did:

- i let my car idle to see when the fan turned on. it turned on a little under half way. great, i said. so i figured i could micro-adjust from here. but as it sat idling, the temp needle kept going and going up.

- so I made sure that the air was being pushed into the engine. i put a piece of toilet paper in front of the fan. it sucked it right into the fan cage (didnt chop up the paper). so at the very least i knew it was going in the right direction. i did put my hand on the other side, but it didnt seem that that much air was being pushed thru. this being my first e-fan, i didn't and still dont know how much air you should be feeling on the engine side.

- i turned on the heater fan and left the engine running. so it was slooooly decreasing the needle downwards. good sign, but after about 5-10 mins, it didn't push the temp down. it was just holding

So I'm wondering...

1) is the fan i bought too low CFM?

2) does the fan blades need to be turned over? Is that why its not pushing as much air as i expected?

3) is the trigger point of the fan too low?

any help would be great.

thanks,

bob

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hi gents,

- bled cooling system by running heater on full blast and ran for nearly 20 minutes

Bob - you might have an air pocket in the cooling system. May need to "burp" the system by jacking up the front of the car and squeezing the bottom radiator hose while the cap is off.

Jim Gerock

 

Riviera 69 2002 built 5/30/69 "Oscar"

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....CONT. still has air pockets?

is the heater HOT all the time?

or does the it get cooler

as the temp gauge climbs?

blown head gasket?

where do you live? what is your outside temp??

you have to raise the front of the car while getting air

out of the system, and drive it more, and leave the heater on

BROIL as an indicator that you still have HOT water circulation

all the time. If the heater turns cooler - you have air pockets

history of motor? - over-heats by you or other owners ?in past 30 years?

cracked head may not be mixing coolent and oil - yet -

but can cause the air pockets now

p.s. you don't need an aux fan.

your trying to fix an already existing basic problem

try pressure testing the system when hot, leave the pressure tester

on the radiator pumped up to 14 - 16 psi for a few hours,

remove the spark plugs and after cooling for 2 hours, crank

over the motor and see if any coolent comes pumping

out of the plug holes.

Have a helper turn the key while you stare at the plug holes.

PROTECT YER EYES!

'86 R65 650cc #6128390 22,000m
'64 R27 250cc #383851 18,000m
'11 FORD Transit #T058971 28,000m "Truckette"
'13 500 ABARTH #DT600282 6,666m "TAZIO"

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Bob - you might have an air pocket in the cooling system. May need to "burp" the system by jacking up the front of the car and squeezing the bottom radiator hose while the cap is off.

jgerock,

i have not done that, i will give it a go today. thanks for the tip.

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CD,

My responses:

- i live in so california. outside temp last night was in the 70s. Today is projected mid 90s.

So yes, last night I ran it around the block for about 10 - 15. The heater was burning my leg on the highest setting so I had to turn it down. If it got cooler, i definitely didnt notice it.

it did have a blown head gasket and cracked head. i had a local shop replace both. motor had 77K. seems to me the PO did not realize the radiator was not good and let the engine overheat.

i removed the stock red fan blades and replaced with the electric fan. if this continues, I will add the fan blades back.

i dont have a pressure tester, ill see what the cost is to try this.

Thanks, CD.

Bob

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My elec fan which is a SPAL high performance unit comes on just above half way and turns off at half way....this takes less than 30 seconds usually at idle. then a minute or so to get back up to turn on temp then again a 30 second burst and the temp goes down. While driving the fan rarely comes on as the airflow from moving is enough to keep the temps below the fan turn on temp. I am using a2 port water neck and a stock BMW fan switch in it. I have a stock 2 core early 2002 radiator and a stock 80 degree Tsatat and 86 degree (or 90?) degree fan switch. Either the cooling system needs to be burped, or the fan isn't running fast enough. It seems to come on at the correct temp, but you are not getting enough cooling. Was it working well with your motor driven fan? The key is to have a GOOD WORKING cooling system before an electric fan install....

1976 BMW 2002 Fjord Blue Ireland Stage II • Bilstein Sports • Ireland Headers • Weber 38 • 292 Cam • 9.5:1 Pistons • 123Tune Bluetooth 15" BBS

2018 BMW M550i X-Drive

1964 Volvo Amazon Wagon
http://www.project2002.com

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My elec fan which is a SPAL high performance unit comes on just above half way and turns off at half way......Was it working well with your motor driven fan? The key is to have a GOOD WORKING cooling system before an electric fan install....

jrhone,

which spal fan do you have? what is the fan diameter? as you said, it might be that the fan doesn't have the required CFM or too small in diameter.

yeah, i have had problems with cooling which is why i believe it had a cracked head when i bought it. so that's why when i had it rebuilt, i put in a lower thermostat 71C vs the standard 80C just in case. so when i saw that this was only offering marginal improvement, there were times where i would drive only 3 miles and then the temp would be above normal and would be bleching coolant. so my final steps were to see if a re-cored radiator and an electric fan would solve my cooling problems.

...now the story has come full circle :)

looks like I need to do some burping tonight.

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Where is the thermostat probe located?

chris,

if you are viewing from the engine side, the probe is located right below and a little to the right of the rad inlet (top hose). its where the hayden instruction manual said to install it, so thats where it went

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Wow, I can't believe I missed this. When I bought my 02, this piece of tube was not installed. I did not notice it missing until now. It looks like a tube which allows air to be fed to the air pump. Could this effect my car's cooling ability (why it overheats at idle?)

any 76 owners out there: what is this tubing made of? i am wondering if i can find material at home depot as a substitute

post-19655-13667647248386_thumb.jpg

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In some cases the fan blade does need to be reversed. On my fan, the instructions state that for a pusher fan "reverse the polarity of the connections and to flip the blade". You may want to take the fan out and check to see what set up produces the best air flow.

Carl

1969 1600 Cabriolet Ti engine

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Re air pump ? the tube is a rubber hose, has nothing to do with overheating.

How far away is the fan from rad fins ? or is it mounted on the fins

Arizona,

Thanks, much appreciated for the reply on the hose and its non-effect on my problem.

The fan is mounted directly to the radiator itself. I made some custom aluminum mounting tabs to affix it to the back side (headlight not engine side) of the radiator.

On another note, I have a Bosch electric fan that I bought as part of an AC part out from a local member. I hooked it up to the battery this morning and wow, the amount of air it pushed was so much greater (can't quantify) than the Hayden I installed. So in addition to burping possible air out of the system, I will install the Bosch fan and see if both make a difference. However, I will burp, then test. If that doesn't work, I'll install the Bosch fan and then see if that solves the problem.

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The Achilles heel of my car has always been cooling. I have learned over the years that my car runs hot with a 50/50 mix. So I run about 15% antifreeze/85% water. And lots of Wetter Water.

I have that mix in there now and it's running as cool as the proverbial cucumber, and doesn't heat up significantly at idle. And I'm using a 71C thermostat.

Cheers,

Carl

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